Walkera HM 4#6 BELL 4 Channel RC Helicopter Brushless Version RTF Simple swashplate control system together with Bell-Hiller mixing structures makes the flight more stables to satisfy different flyers with relaxation Adopting high efficient shaft driven system infinitely reduces the extra waste of the power system Mature low voltage driven systerm presents green, environmental friendly and safety concept Low voltage and high torque brushless motor can provides strong and durable power Mini size 4-channel helicopters for indoor. It offers 9-10 minutes flight time after full charged